Traditionally, windows for use in sailboats, motorboats, yachts, camper trailers, house trailers, and the like were fabricated of glass mounted in metal frames. For large boats, such as luxury yachts, the frames are made of brass, stainless steel, or other corrosion resistant metal. These frame materials, however, are quite expensive and their use is not justified in the smaller windows required for sailboats, motorboats, and camper trailers, for example.
In smaller recreational vehicles, such as boats, camper trailers, and the like, the practice was to fabricate the window frames of bent extruded aluminum shapes. Aluminum, however, is susceptible to corrosion, especially in salt atmospheres such as are encountered in marine applications. Corrosion of aluminum window frames may be prevented by painting the frame, but this maintenance effort is not always pursued; also, paint does not adhere readily to aluminum, with the result that where a diligent painting program is pursued the window frames must be repainted frequently.
In an effort to overcome the disadvantages associated with aluminum frames, a window having a frame fabricated of thermoplastic material was introduced commercially for use in small boats. This product has a pane of transparent synthetic resin and a one-piece frame fabricated of vacuum-formed ABS resin to which the pane is bonded. Because the frame is fabricated by vacuum forming techniques, the thickness of the frame material necessarily is relatively thin. Accordingly, these windows flex readily and the bond between the pane and the frame may break in response to such flexing. These windows have the advantage that they are made entirely of synthetic materials which are resistant to corrosion and which can be colored to harmonize with the remaining structure in which they are installed. These windows, because of their one-piece frame construction, are either bonded or screwed to the basic boat structure peripherally of the window opening. Where provided, an interior trim frame is bonded or screwed to the interior of the boat structure for the purpose of ornamentation.
Recently, in an effort to overcome the disadvantages associated with aluminum frames and the disadvantages associated with vacuum formed ABS resin frames, a window having a frame fabricated of extruded rigid vinyl resin was introduced commercially. The extruded resin frame has the rigidity of aluminum shapes and the corrosion resistance of the ABS vacuum formed shapes. This window generally has replaced windows with aluminum or ABS vacuum formed frames in better quality boats.
A problem common to all of these windows which utilize a frame is one of high cost, because these frames are expensive to fabricate and attach to a boat hull. It is much simpler and cheaper to directly bolt plastic sheets to the side of a cabin to form a window. However, even direct bolting has disadvantages, in that the manual labor required for bolting is costly, and the rough edge of the hole in the side of the cabin is unsightly.
The development of some of the newer adhesives, particularly the silicone cements and polysulfide rubbers, has made it possible to cement plastic panes to fiberglass sides rather than by bolting, thereby reducing the installation costs. However, there still remains the problem of the unsightly edge of the window hole in the side of the cabin. In addition, since the sides of boat cabins often flex in use, there is a tendency for the plastic panes to be separated from the boat hull.
Some companies have molded frames directly into the cabin side and have cemented the plastic panes into these frames. However, this involves complex molds and the difficult operation of removing the cabin sides from the molds. Also the edges of the panes have to be beveled, thereby increasing the expense of the window.